Building a Campus Makerspace? Here’s How to Plan for Safety When Adding CNC Machines
Whether you’re creating a campus makerspace from scratch or wanting to add CNC (computer-numerically controlled) machines to your space’s tool offerings, there are a number of logistical and safety concerns to bear in mind. Depending on the type of machines you’re considering and the rules and regulations of your campus, different categories of safety concerns may come into play.
Prior to working at Other Machine Co., I was a graduate student at the University of Texas at Austin and managed a materials science lab of 15 students in the Mechanical Engineering Department. We often wanted to purchase new equipment for synthesis and characterization, but I quickly learned that you can’t always just purchase a machine and install it in your lab on campus. Navigating the regulations for the specific piece of equipment and staying compliant with the facilities management is doable if you know what to look for and can come to those conversations prepared. Part of my new role is advising institutions on building out their spaces for fabrication and helping people spot potential problems before they impact the timeline and budget for the makerspace.
This article is intended to help you become aware of some things you might need to prepare for when deciding which CNC machines to include in your makerspace. It should only be considered a guide and doesn’t include all of the baseline safety information, like proper use of personal protective equipment. Please consult the facilities or property manager of your specific location to review the limitations of your facility.
This article was written with help from Tackett Austin of Advanced Prototype Engineering(APROE), a San Francisco-based design and engineering firm specializing in the development of mechanical and mechatronic prototypes, as well as machine shop setup. APROE was responsible for outfitting Autodesk's Pier 9 facility.
Top Five Safety Categories
1. Bodily Harm
When it comes to bodily harm, it’s important to differentiate between the different degrees of severity. Some institutions refer to these as zones: green, yellow, and red. These colors correspond to what safety consequences there might be for operating the machines within that zone. “Band-aid,” “hospital trip,” and “fatal,” correspond to green, yellow, and red zones, respectively. It might seem extreme to highlight which machines can result in fatal levels of bodily harm in the red zone, but students can still be allowed access to these machines if the proper safety precautions and training methods are employed. If your fabrication space will have extended hours or be staffed by volunteers, you should probably limit your inclusion of machines to those that are in the “green zone.”
Some machines, such as laser cutters, use a laser beam to cut material, and if used improperly, they can start fires that get out of control. You may have to place these machines in certain areas and/or supplement the standard fire extinguishers in the room with sprinklers or a fire sand bucket. Installing these additional fire protections can lengthen the schedule for setting up your space and can influence your budget planning, as more infrastructure can add significant expense.
One other source of fire hazard that many people don’t realize is that from 3D printers. Some 3D printers require the use of flammable solvents to cure and clean the parts that they print. Those flammable solvents may require special storage cabinets, depending on the rules of your facility.
The two types of ventilation concerns for makerspaces are fumes and particulates. Both fumes and particulates can lead to fire, but each is a hazard on its own. Whether your makerspace is in a dedicated room or is part of a computer lab or library, you may be significantly limited by the requirements of your facility. Because laser cutters must burn material in order to cut through or make a mark, every cut by a laser cutter gives off a smell and at least a small amount of smoke. Depending on the style of laser cutter, you may need a full vent hood to operate the machine.
One of the biggest hazards with laser cutters is the cutting of polyvinyl chloride (PVC). Cutting PVC with a laser results in the production of hydrochloric acid and chlorine gas. Even with proper ventilation, users must avoid cutting certain materials.
The resins and solvents used by certain 3D printers may also warrant additional ventilation depending on the rules of your facility. Resin exposure may cause allergic reactions, asthma symptoms, breathing difficulties, or general respiratory irritation if inhaled. At some facilities, filament-style 3D printers must also be ventilated, but this is less common.
Particulate ventilation and filtration is necessary with the operation of large-format milling machines and table routers. Typically these machines are purchased with an external vacuum and filtration unit to trap particles during operation. Be sure to include these filtration units in your budget.
4. Electrical Requirements
Larger machines often have electrical requirements that are beyond normal wall outlet power. This is less of a safety hazard and more of a budgetary hazard. Before you commit to the list of machines you’d like in your space, make sure the space either already has the proper power outlets required by your machines, or make sure your facility will cover the cost of installing the proper electrical system. Upgrading to the proper electrical system can be pricey and time-consuming if you’re not prepared for it ahead of time.
5. Materials Handling
The solvents and resins used by some types of 3D printers must be properly stored and disposed of, and the user must be protected from exposure. You should consult the material safety data sheet (MSDS) for each type of resin used by the 3D printer, but most resins can cause skin irritation, serious eye irritation, and allergic skin reactions and can be harmful to aquatic life if poured down the drain. Because of this, your facility may require installation of an eye-wash station and require disposal of contaminated materials, spent resin, and cleaning solvent through the standard hazardous waste disposal procedures followed by other labs on campus. It’s important to know the storage and disposal requirements ahead of time so that you can budget for the right equipment and include waste disposal in the training process for your makerspace.
Questions, comments, or concerns about adding CNC milling machines to your makerspace? We'd love to hear from you!
Safety Factors for Different Classes of Machines
Knowing what you’re getting into with different machines can save you a lot of time and help you budget properly when getting your space up and running. The situation you want to avoid is having your machines sitting in boxes while you wait two months for proper ductwork or solvent cabinetry to be installed. You also want to avoid the struggle of finding a few thousand extra dollars in a budget to cover upgrading an electrical system in an older building so that your machines can be installed.
This section calls out machine-specific safety considerations to be aware of and gives a few examples of the types of machines in each category. For our purposes, we’ve limited the analysis to machines that are the most commonly used within fabrication spaces on college campuses. This list is ranked in the order of relative safety for context and marked with color ratings that designate the access zone where they are most commonly found within their fabrication space.
3D Printers: Filament (FDM)
These machines are the safest on our list, which is one reason they’re so popular in fabrication spaces. They do have a heating element that melts the plastic filament while the machine is printing, but it’s similar to the risk of using a hot glue gun. Many facilities deem filament (FDM) 3D printers safe enough for 24/7 use, and self-training is often used for certification.
Examples: Zortrax, Printrbot Simple, Ultimaker, Makerbot
Enclosed CNC Milling Machines with Safety Windows
This type of machine uses a sharp cutting tool that must be loaded into the machine by hand and could produce a minor cut if done improperly. Safety lockout windows on these models turn off the cutting tool when the machine is opened. Self-training is also adequate for operating these machines safely.
Examples: The Bantam Tools Desktop PCB Milling Machine, Roland SRM-20
Class 1, 2, and 3R Laser Cutters
Toxic Fumes from Improper Use
Even though Class 1 laser cutters is safe enough to be used in the home, on-campus facilities may require you to address the fire hazard inherent with all laser cutters. A small, match-sized flame in a laser cutter is a common occurrence, and all users need training on how to extinguish a small fire. It's usually as simple as lifting the lid or placing a damp cloth on the fire. Damp paper towels will knock down most smaller fires without damaging the hardware. A laser should never be unattended.
Most bench-top or consumer Class 1 laser cutters are equipped with safety systems, like safety interlocks and special filters in the glass top, that limit exposure to the laser, and eye protection is not required during use.
Unvented laser cutters require filtration that allows them to be used anywhere without any special ventilation. Many small lasers use fans and filters for removing smoke, but a powered ventilation system will allow for broader use of materials. Toxic fumes can be avoided by proper training. Cutting any plastic with vinyl must be avoided; even if fully ventilated to the outside, the fumes contain chlorine gas and will damage internal parts of the laser. You should consider the ongoing cost and the lifetime of the filtration system when budgeting for your space. Because of the risk of users attempting to cut plastics such as PVC, laser cutters in this category are housed in the yellow zone within fabrication spaces.
These machines also generally require a dedicated 120V circuit.
Note: A CO2 extinguisher (Class B) is not designed for a paper or wood fire but will fill the chassis of the laser cutter with CO2 and can handle most moderate-sized fires in a laser. A Class A extinguisher is designed for paper and wood fires but will generally cause damage to electronics. The Halotron I Clean Agent extinguisher is also a good option for lasers and won't damage electronics.
Examples: Glowforge (Class 1), Epilog Zing (Class 3R), Universal Laser Systems’ VLS Series (Class 1, 3R)
3D Printers: Stereolithography, Resin (SLA)
Flammable, Volatile Solvents
Organic Resin Storage
Solvent Waste Disposal
Flammable solvents may require special storage and waste disposal. Depending on your facility, you may have additional requirements for ventilation of vapors or eye wash station installation. Even though the operation of SLA 3D printers is very safe, they’re often in the yellow zone because of the increased safety, disposal, and ventilation requirements for the solvents and resins used to make their prints.
Examples: Form 2, Ember
Large-Format CNC Routers
These machines are large enough to cause significant bodily harm if used improperly. For this reason, more involved training and limited access is required. Most machines in this class are large and completely open and can cause significant bodily harm to an untrained operator.
Filtration systems are necessary to remove particles from the air during their operation, so these machines should be connected to a dust-collection system. However, it’s difficult to collect all the particulates on machines that are not fully enclosed. They are designed to cut rigid foams and wood (many machines in this class have a bed size of 4'x8' or larger, to fit a full sheet of plywood). Larger machines should be installed away from other equipment or in a separate room.
These can also be some of the loudest machines in a shop, and so noise must be a factor in determining where the machine is situated in the shop. These machines also generally require a minimum of a 240V circuit to operate, but larger machines require many amps of three-phase power.
Examples: ShopBot (all models), Diversified Machine Systems, Laguna IQ
Large-Format CNC Milling Machines
The largest of these machines are fully enclosed and can be configured to only perform slow movements when the doors are open. Physical safety is not a large risk on fully enclosed machines. If the machine is not fully enclosed, it presents much higher risk to untrained operators. Smaller machines may be open.
These machines are designed to work with plastic and metal rather than wood, and so they produce chips rather than particulates, which need to be filtered. They also generally require a minimum of a 240V circuit, but larger machines require many amps of three-phase power. Many also require water and compressed air.
Examples: Tormach, Haas, ProtoTRAK
Class IV Industrial Laser Cutters
Bodily Harm (Eye and Skin Damage)
Even though they operate the same way as smaller laser cutters, Class IV laser cutters generally produce more power, which can create a fire more quickly. They are the most powerful and dangerous class of laser cutter. Many industrial laser cutters have openings in the chassis where an operator could potentially be injured from contact with the laser beam, requiring extra training. Many metal-cutting lasers are in this class. Because of the ventilation, electricity, and fire protection requirements, this class of laser must be located in the red zone of fabrication spaces, and access must be limited to users with more significant training.
Compressed gasses (other than air) can be used to cut metal and other materials the smaller lasers cannot; plan extra space for gas cylinders as well as spares. Powered ventilation and dry, compressed air are required. These machines generally require a dedicated 240V circuit.
Example: Coherent Metabeam
CNC machines can open up a world of possibilities for the students on your campus, and by knowing the safety concerns and setup requirements in advance, you can seamlessly integrate them into your makerspace, ensuring a positive experience for all. At Other Machine Co., we’ve seen first-hand how empowering these 21st-century tools can be when integrated into higher education curricula, and we're happy to share our knowledge.